Cryptography with Python using Fernet
3 min read
Let us look at how to encrypt text and files using Python. For this we are going to be using Fernet which is a part of python's cryptography package
So let us get right into it
Ok firstly we need to downloaded the cryptography package using
pip install cryptography
pip3 install cryptography
After we have executed the command in the terminal, we are ready to start coding.
You might want to use your favourite code editor (vscode, sublime text, atom etc...) or any IDE.
Now let us first import the required library
from cryptography.fernet import Fernet
Then we are going to define a function that will write the key to a file
def write_key(): key = Fernet.generate_key() # Generates the key with open("key.key", "wb") as key_file: # Opens the file the key is to be written to key_file.write(key) # Writes the key
We will also write down a function that will help with reading and loading the key into a variable
def load_key(): return open("key.key", "rb").read() #Opens the file, reads and returns the key stored in the file
Now let us take the message we are going to encode as user input and encode it to bytes because that is how fernet works
message = input("Message: ").encode() # Takes the message as user input and encodes it
Now we need to write are top secret key to the key file. We are going to run this only once and then comment the line out because we don't want it to write a new key down every time the code is run.
write_key() # Writes the key to the key file
Now we need to load the key i.e. read the key from the key file and store it in a variable called as
key though you can name it whatever you want
key = load_key() # Loads the key and stores it in a variable
Now we need to initialize the fernet object by passing in the key we just loaded
f = Fernet(key)
Now let us get to the main part, encrypting the message Also let us print it out
encrypted_message = f.encrypt(message) print(encrypted_message)
You see that the encrypted message cannot be understood by anyone so it is safe now and will be the same unless decrypted with the same key
To decrypt, it is a very similar process
decrypted_message = f.decrypt(encrypred_message) print(decrypted_message)
So here, first the message is encrypted and is printed out and then we decrypt it and print it in the next line. If the initial message and the decrypted message are the exact same, our code has worked!!!
So that was it for this tiny blog (and it was my first blog ever so leave down some feedback!!!)
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